#score {
  text-align: center;
}

h2 {
  text-align: center;
}

div {
  margin: 0 auto;
  width: 100px;
  height: 100px;
}

#main {
  width: 400px;
  height: 400px;
  background: white;
  border: 2px solid gray;
  margin: 0 auto;
  overflow: hidden;
  position: relative;
  display: flex;
  justify-content: center;
}

#con {
  width: 100%;
  height: 400px;
  position: relative;
  top: -100px;
  /*隐藏最上层的那行*/
  border-collapse: collapse;
}

.row {
  height: 100px;
  width: 100%;
}

.cell {
  height: 100px;
  width: 100px;
  float: left;
}

.black {
  background: black;
}
.button{
  position: absolute;
  bottom:30px;
  cursor: pointer;
}